Fuse of semiconductor device and method for manufacturing the same

ABSTRACT

A method for manufacturing a fuse of a semiconductor device comprises forming an island-type metal fuse in a region where a laser is irradiated, so that laser energy may not be dispersed in a fuse blowing process, thereby improving repair efficiency.

CROSS-REFERENCE TO RELATED APPLICATION

Priority to Korean patent application number 10-2007-137981, filed on Dec. 26, 2007, the disclosure of which is incorporated by reference in its entirety, is claimed.

BACKGROUND OF THE INVENTION

The invention relates generally to a fuse of a semiconductor device and a method for manufacturing the same and, more specifically, to technology for forming an island-type metal fuse in a region where a laser is irradiated so that laser energy may not be dispersed in a fuse blowing process, thereby improving repair efficiency.

In manufacturing semiconductor devices, if even a single fine cell of the device has a defect, the device does not serve as a memory, and is treated as a defective device.

However, it is inefficient to disuse the device as defective when a cell of the memory has a defect.

In some cases, a redundancy cell which is previously installed in the memory device is replaced with a defective cell to repair the entire memory, thereby improving yield.

The repair method using a redundancy cell includes replacing a normal word line having a defect or a normal bit line having a defect with a redundancy word line or a redundancy bit line which is disposed in each cell array.

When a defective cell is found through a test after processing a wafer, an internal circuit performs a program to replace an address corresponding to the defective cell with an address of a redundancy cell. As a result, in use an address signal corresponding to the defective cell is inputted to access data of the redundancy cell, which is replaced corresponding to the defective cell.

Generally, the program system includes burning and blowing a fuse with a laser beam to replace a path of an address. As a result, a common memory device includes a fuse unit configured to replace an address path by irradiating and blowing (opening) a fuse with a laser. A “fuse” refers to a line cut by irradiation of laser, and a “fuse box” refers to the cut site and its surrounding region.

The fuse unit has a plurality of fuse sets. One fuse set can replace an address path. The number of fuse sets in the fuse box corresponds to the number of redundancy word lines or redundancy bit lines in the memory device.

In general, a method for fabricating a semiconductor device includes forming and planarizing an interlayer insulating film over a fuse region of a semiconductor substrate, forming a plurality of fuses over the interlayer insulating film, and forming an insulating film over the semiconductor substrate to cover the fuses.

A partial thickness of the insulating film is etched to form a fuse open region so that the insulating film having a given thickness may remain on the fuse of a local blowing region. The fuse open region is then irradiated with laser, and a blowing process is performed to cut a given metal fuse.

The remaining insulating film generally has a thickness ranging from 1000 Å to 3000 Å over the fuse. However, laser energy is not absorbed in the insulating film but passed through the insulating film because the insulating film has a transparent property such as glass. As a result, most laser energy is absorbed by the fuse. The fuse is thermally expanded by the laser energy, and the insulating film surrounding the fuse is broken when the thermal expansion reaches a critical point. As a result, most of the residual fuse is vaporized.

The fuse is not formed by an additional process but by using an electrically conductive layer including a bit line, a word line, or a plate line of a capacitor. As the device is highly-integrated in 60 nm, a fuse is formed using a metal line formed on the plate line.

When the fuse is formed with a metal line, the fuse typically has a resistance smaller than that of the plate line by ten times, with excellent thermal conductivity. However, the excellent thermal conductivity disperses laser energy in the blowing process, so that the fuse may not be cut.

BRIEF SUMMARY OF THE INVENTION

Various embodiments of the invention are directed at providing a method for manufacturing a fuse of a semiconductor device that comprises forming an island-type metal fuse in a region where a laser is irradiated so that laser energy may not be dispersed in a fuse blowing process, thereby improving repair efficiency.

Various embodiments of the invention are directed at reducing a fuse area of a region where a laser is irradiated to decrease the amount of laser energy required in fuse cutting, thereby improving efficiency and productivity.

Various embodiments of the invention are directed at reducing cost without additional equipment for cutting a metal fuse.

Various embodiments of the invention are directed at electrically connecting a metal fuse separated from an island-type metal fuse through a concave-shaped conductive film to disrupt transmission of lost laser energy in a horizontal direction.

According to an embodiment of the invention, a method for manufacturing a fuse of a semiconductor device comprises forming a blowing fuse portion and a non-blowing fuse portion horizontally spaced from and aligned with each other at the same level, and forming an electrically conductive connecting portion connecting the blowing fuse portion to the non-blowing fuse portion, wherein the electrically conductive connecting portion is formed at a lower level than the level of the blowing and non-blowing fuse portions.

The electrically conductive connecting portion is preferably formed by forming an etch-stop pattern over a semiconductor substrate; forming an insulating film over he semiconductor substrate and on the etch-stop pattern; etching the insulating film to form a contact hole that exposes the etch-stop pattern; depositing an electrically conductive layer on the insulating film and in the contact hole; and etching an overall surface of the electrically conductive layer until the insulating film is exposed.

The etch-stop pattern preferably comprises a polysilicon layer. The insulating film preferably comprises an oxide layer. The insulating film preferably has a thickness ranging from 21000 Å to 23000 Å. The electrically conductive layer preferably comprises a tungsten layer, and is preferably deposited with a thickness ranging from 2100 Å to 2300 Å. The electrically conductive layer resulting from the etching process is preferably formed at a bottom portion and sidewalls of the contact hole. The electrically conductive layer preferably remains in the contact hole with a thickness ranging from 900 Å to 1100 Å after the etching process.

The blowing fuse portion and the non-blowing fuse portion are preferably formed by forming a metal line on the conductive layer and the insulating film, and selectively etching the metal line until the electrically conductive layer is exposed. The metal line preferably comprises an aluminum layer. The metal line preferably has a thickness ranging from 3900 Å to 4100 Å.

According to an embodiment of the invention, a fuse of a semiconductor device comprises: a blowing fuse portion; a non-blowing fuse portion horizontally spaced from and aligned with the blowing fuse portion, wherein the blowing portion and the non-blowing portion are arranged at the same level; and an electrically conductive connecting portion, located at a lower level than the blowing and non-blowing fuse portions and connecting the blowing fuse portion to the non-blowing fuse portion. The electrically conductive connecting portion preferably has a concave shape.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view illustrating a fuse of a semiconductor device according to an embodiment of the invention.

FIGS. 2 a to 2 f are cross-sectional views illustrating a method for manufacturing a fuse of a semiconductor device according to an embodiment of the invention.

FIG. 3 is a perspective view illustrating a product of the method for manufacturing a fuse of a semiconductor device according to an embodiment of the invention.

DESCRIPTION OF EMBODIMENTS

FIG. 1 is a plan view illustrating a fuse of a semiconductor device according to an embodiment of the invention.

Referring to FIG. 1, a fuse 20 a is formed in a blowing region of a semiconductor substrate 10. A fuse 20 b is separated from the fuse 20 a in a major-axis direction of the fuse 20 a and formed in a non-blowing region. The fuse 20 a is electrically connected to 20 b through an electrically conductive film 18 which is a connecting portion. The conductive film 18 illustratively and preferably has a concave shape. For example, the concave shaped is “U”.

FIGS. 2 a to 2 f are cross-sectional diagrams illustrating a method for manufacturing a fuse of a semiconductor device according to an embodiment of the invention, taken along A-A of FIG. 1.

Referring to FIG. 2 a, an etch-stop film (not shown) and a first barrier metal layer (not shown) are formed over a semiconductor substrate 10 of the fuse region. The process for forming the etch-stop film is illustratively performed with a process for forming a plate electrode layer of a cell region. The etch-stop pattern preferably comprises a polysilicon layer. The first barrier metal layer preferably comprises a titanium nitride (TiN) film.

The first barrier metal layer and the etch-stop film are selectively etched to form a first barrier metal pattern (not shown) and an etch-stop pattern 12 that expose the semiconductor substrate 10 of the blowing region.

Referring to FIG. 2 b, a planarized insulating film 14 is formed over the semiconductor substrate 10, the first barrier metal pattern, and the etch-stop pattern 12. The insulating film 14 preferably comprises an oxide film and preferably has a thickness ranging from 21000 Å to 23000 Å.

Referring to FIG. 2 c, the insulating film 14 is selectively etched to form a contact hole 16 that exposes the etch-stop pattern 12.

Referring to FIG. 2 d, a second barrier metal layer (not shown) and an electrically conductive film 18 are formed over the insulating film 14 including the contact hole 16. The second barrier metal layer preferably comprises a titanium (Ti) film, preferably having a thickness ranging from 45 Å to 55 Å. The electrically conductive film 18 preferably comprises a tungsten (W) film, preferably having a thickness ranging from 2100 Å to 2300 Å.

The conductive film 18 is blanket-etched to expose the insulating film 14. The blanket-etching process of the electrically conductive film 18 is preferably performed by an etch-back method. The electrically conductive film 18 is formed at a bottom portion and sidewalls of the contact hole 16. The electrically conductive film 18 remains in the bottom portion of the contact hole 16 and preferably has a thickness ranging from 900 Å to 1100 Å.

Referring to FIG. 2 e, a third barrier metal layer (not shown), a fuse material film 20, and a fourth barrier metal layer (not shown) are formed over the resulting structure. The third barrier metal layer preferably has a deposition structure including a Ti film, preferably having a thickness ranging from 95 Å to 105 Å and a TiN film, preferably having a thickness ranging from 190 Å to 210 Å.

The fuse material film 20 includes a metal line material (Al, for example) preferably having a thickness ranging from 3900 Å to 4100 Å. The fourth barrier metal layer preferably has a deposition structure including a Ti film, preferably having a thickness ranging from 90 Å to 110 Å and a TiN film, preferably having a thickness ranging from 760 Å to 840 Å.

Referring to FIG. 2 f, the fuse material film 20 is selectively etched to expose the conductive film 18. The fuses 20 a and 20 b are formed over the insulating film 14 of the blowing region and the insulating film 14 of the non-blowing region. That is, the fuses include the blowing region 20 a and the non-blowing region 20 b, which are electrically connected through the electrically conductive film 18.

FIG. 3 is a diagram illustrating a product of the method for manufacturing a fuse of a semiconductor device according to an embodiment of the invention.

Referring to FIG. 3, the fuse 20 a of the blowing region is formed to have an island type, thereby reducing an area where a laser is irradiated in the blowing process. As a result, loss of laser energy is prevented, and the fuse 20 a can be cut with small laser energy. Although a partial laser energy may be lost by the electrically conductive film 18, the electrically conductive film 18 is illustratively formed in a concave shape to minimize loss of the laser energy.

The fuse 20 a is separated from the fuse 20 b, so that the laser energy absorbed by the fuse 20 a during the blowing process may be prevented from being transmitted into the fuse 20 b. The insulating film 14 is formed between the fuses 20 a and the 20 b, so that the laser energy may be transmitted through the electrically conductive film 18, thereby preventing vertical loss of the laser energy.

The fuse 20 a has a resistance smaller than that of a plate fuse and larger than that of a metal fuse. The fuse 20 a has thermal consumption smaller than that of the metal fuse and the plate fuse. As a result, the loss of the laser energy condensed in the fuse 20 a during the blowing process is minimized, so that it is easy to cut the fuse.

As described above, according to an embodiment of the invention, a method for manufacturing a fuse of a semiconductor device comprises forming an island-type metal fuse in a region where a laser is irradiated so that a laser energy may not be dispersed in a blowing process, thereby improving repair efficiency.

The method reduces a fuse area of a region where a laser is irradiated to decrease a laser energy required in fuse cutting, thereby improving efficiency and productivity.

The method reduces cost without additional equipment for cutting a metal fuse.

The method includes electrically connecting a metal fuse separated from an island-type metal fuse through a preferably concave-shaped conductive film to disconnect a laser energy that is lost in a horizontal direction.

The above embodiments of the invention are illustrative and not limiting. Various alternatives and equivalents are possible. The invention is not limited by the type of deposition, etching, polishing, and patterning steps described herein, nor is the invention limited to any specific type of semiconductor device. For example, the invention may be implemented in a dynamic random access memory (DRAM) device or non volatile memory device. Other additions, subtractions, or modifications are obvious in view of the disclosure and are intended to fall within the scope of the appended claims. 

1. A method for manufacturing a fuse of a semiconductor device, the method comprising: forming a blowing fuse portion and a non-blowing fuse portion horizontally spaced from and aligned with each other at the same level, and, forming an electrically conductive connecting portion connecting the blowing fuse portion to the non-blowing fuse portion, wherein the electrically conductive connecting portion is formed at a lower level than the level of the blowing and non-blowing fuse portions.
 2. The method according to claim 1, comprising forming the electrically conductive connecting portion by: forming an etch-stop pattern over a semiconductor substrate; forming an insulating film over the semiconductor substrate and on the etch-stop pattern; etching the insulating film to form a contact hole that exposes the etch-stop pattern; depositing an electrically conductive layer on the insulating film and in the contact hole; and etching an overall surface of the conductive layer until the insulating film is exposed.
 3. The method according to claim 2, wherein the etch-stop pattern comprises a polysilicon layer.
 4. The method according to claim 2, wherein the insulating film comprises an oxide layer.
 5. The method according to claim 2, wherein the insulating film has a thickness in the range of 21000 Å to 23000 Å.
 6. The method according to claim 2, wherein the electrically conductive layer comprises a tungsten layer.
 7. The method according to claim 2, comprising depositing the electrically conductive layer with a thickness in the range of 2100 Å to 2300 Å.
 8. The method according to claim 2, comprising forming the electrically conductive layer resulting from the etching process at a bottom portion and sidewalls of the contact hole.
 9. The method according to claim 2, wherein the electrically conductive layer remains in the contact hole with a thickness in the range of 900 Å to 1100 Å after the etching process.
 10. The method according to claim 2, comprising forming the blowing fuse portion and the non-blowing fuse portion by: forming a metal line on the electrically conductive layer and the insulating film; and selectively etching the metal line until the electrically conductive layer is exposed.
 11. The method according to claim 10, wherein the metal line comprises an aluminum layer.
 12. The method according to claim 10, wherein the metal line has a thickness in the range of 3900 Å to 4100 Å.
 13. A fuse of a semiconductor device comprising: a blowing fuse portion; a non-blowing fuse portion horizontally spaced from and aligned with the blowing fuse portion, wherein the blowing fuse portion and the non-blowing fuse portion are arranged at the same level; and an electrically conductive connecting portion, located at a lower level than the blowing and non-blowing fuse portions and connecting the blowing fuse portion to the non-blowing fuse portion.
 14. The fuse according to claim 13, wherein the electrically conductive connecting portion has a concave shape. 